JP2000128509A - Production of oxide thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a oxide thin film having a uniform thickness. SOLUTION: This process consists in adding a fluorine capturing agent into an aqueous solution containing a fluorometal complex compound and depositing the metal oxide thin film derived from the fluorometal complex compound on a base material immersed into the aqueous solution, in which the deposition of the metal oxide thin film is executed while part of the aqueous solution is continuously or intermittently filtered in the presence of the seed crystal of the metal oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a metal oxide thin film. In particular, the present invention relates to a method for producing a metal oxide thin film having a uniform thickness. The oxide thin film formed by the manufacturing method of the present invention can be applied to a wide range of fields such as photocatalysts, storage element materials, various batteries, sensors, and photonics materials.

[0002]

2. Description of the Related Art Techniques for forming an oxide thin film include a sputtering method, a CVD method, a vacuum evaporation method, a sol-gel method, and an aqueous solution deposition method. Further, as one application of the aqueous solution deposition method, T
there is iO ₂ seed aqueous solution deposition method (Reference: Anataze synt
hesis from aqueous solutionand photo-catalytic act
ivity by Koji Sato in Proceedings of The Sixth Int
ernational Symposium on New Glass).

In the TiO ₂ seed aqueous solution deposition method, (NH
₄ ) ₂ TiF ₆ is dissolved in water, and (NH ₄ ) ₂ TiF ₆ exists in an aqueous solution as TiF ₆ ^2- ions. To this aqueous solution, TiO ₂ anatase powder is added as a seed (seed crystal), and B ₂ O ₃ is further added. B ₂ O ₃ dissolves in the aqueous solution to become BO ₃ ^3- . BO ₃ ^3- is Ti
F constituting F ₆ ^{2-ions -} reacts with ions, Ti
Decomposing F ₆ ^2-ionic, stable BF ₄ ^- to form a complex. The Ti ions generated by decomposition of the TiF ₆ ^2- ions react with oxygen to generate TiO ₂ . Generation of TiO ₂ (precipitated) proceeds the TiO ₂ anatase powder as nuclei, and to produce a TiO ₂ thin film dipped substrate surface in an aqueous solution. These reactions are represented by the following chemical reaction formulas. ^{_{TiF 6 2- + 2H 2 O ⇔}} TiO 2 ↓ + 6F - + 4H + (1) BO 3 3- + 4F - + 6H + → BF 4 - + 3H 2 O (2)

Since the above-mentioned TiO ₂ seed aqueous solution deposition method is carried out under atmospheric pressure and at least around room temperature below the boiling point of the aqueous solution, it does not matter whether the substrate on which TiO ₂ is deposited has heat resistance. Furthermore, since a TiO ₂ thin film having crystallinity can be formed, a TiO ₂ thin film having a photocatalytic action can be generated.

[0005]

The above-mentioned seed aqueous solution deposition method uses a T substrate having a photocatalytic action on a substrate having poor heat resistance.
There is an advantage that an iO ₂ thin film can be generated. However, there is a problem that the thickness of the oxide thin film tends to be non-uniform depending on the location of the substrate, and it is not easy to generate an oxide thin film having a uniform thickness. In particular, when a thin film is deposited in the presence of an oxide seed crystal, the above problem is likely to occur. Accordingly, an object of the present invention is to provide a method for producing an oxide thin film in the presence of an oxide seed crystal, which method can produce an oxide thin film having a uniform thickness.

[0006]

Means for Solving the Problems The present inventors have investigated the cause of the non-uniformity of the thickness of a thin film of a metal oxide such as TiO ₂ by the above-mentioned aqueous solution method. The present invention was completed by finding that the non-uniformity of the thickness can be eliminated by performing the precipitation while continuously or intermittently filtering a part of the aqueous solution for precipitation. In the seed aqueous solution deposition method, fine particles of TiO ₂ grow in the aqueous solution, and the grown fine particles are deposited on the deposition substrate. However, without deposition, some TiO ₂ particles may agglomerate into large particles of several mm in size. When the agglomerated particles adhere to the film forming substrate, the TiO ₂ film cannot be deposited at that location. Large aggregated particles having a size of several mm are particularly large under the condition where seed crystals are present. As a result, the thin film is more likely to be non-uniform than when no seed crystal is used. On the other hand, in the method of the present invention, the above-mentioned problem was solved by filtering the aqueous solution for deposition and removing particles that inhibit the deposition of the thin film from the aqueous solution for deposition.

[0007] Filtration of an aqueous solution for a raw material of an aqueous solution for precipitation is described in PCT / JP97 / 03155. However, the filtration here is used for the preparation of a fluorotitanium complex compound and is intended to prepare an aqueous solution for precipitation by removing undissolved titanium oxide particles, or suspend titanium oxide fine particles. It is intended to remove large particles of titanium oxide in order to prepare an aqueous solution of a seed crystal which is turbid, and among the titanium oxide particles precipitated and formed in the aqueous solution for precipitation, a relatively relatively agglomerated particle size. Are not removed during the deposition step.

The present invention provides a method of adding a fluorine scavenger to an aqueous solution containing a fluorometal complex compound to deposit a metal oxide thin film derived from the fluorometal complex compound on a substrate immersed in the aqueous solution. In the deposition of the metal oxide thin film, in the presence of a seed crystal of the metal oxide,
The present invention relates to a method for producing a metal oxide thin film, which is performed while filtering a part of the aqueous solution continuously or intermittently. Further, the present invention provides the above-mentioned production method, wherein the aqueous solution containing the fluorometal complex compound contains a water-soluble metal compound, and the metal oxide thin film derived from the fluorometal complex compound doped with the metal ion derived from the water-soluble metal compound. The method includes a method for producing a metal ion-doped metal oxide thin film to be deposited.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the production method of the present invention, a metal oxide thin film is deposited while continuously or intermittently filtering a part of the aqueous solution in the presence of a seed crystal of the metal oxide. It is characterized by the following.

In the production method of the present invention, a seed crystal of a metal oxide to be precipitated is added to an aqueous solution, and a metal oxide thin film is deposited in the presence of the seed crystal. By using a seed crystal, any of the precipitated metal oxides becomes a stable phase. The seed crystal is in the range of 0.001 to 10 μm, preferably 0.00.
1 to 1 μm, more preferably 0.001 to 0.15
A fine particle in the range of μm is preferable, and the amount of addition can be appropriately determined in consideration of the amount of the oxide to be precipitated and the like. In the method of the present invention, a precipitate can be obtained as a stable phase by using a seed crystal of a target metal oxide as a seed crystal. Further, the precipitation rate can be controlled by selecting the particle diameter and the amount of the seed crystal. If necessary, seed crystals can be replenished during the precipitation.

[0011] Filtration of the aqueous solution for precipitation can be carried out by using a filter having a pore size that allows the seed crystals to pass through but captures precipitated particles having a particle size larger than the seed crystals.
This is preferable from the viewpoint of maintaining the effect of adding the seed crystal and generating an oxide thin film having a uniform thickness. In particular,
From the viewpoint of generating an oxide thin film having a uniform thickness, it is preferable to use a filter having a pore size of 150 nm or less. The pore size of the filter is more preferably 100n
m, more preferably 50 nm or less. The filtration can be performed by continuously or intermittently circulating an aqueous solution for precipitation through a filter. Specifically, a part of the aqueous solution for precipitation is extracted and passed through the filter. Then, the obtained aqueous solution is returned to the aqueous solution for precipitation again. The amount (circulation amount) of the aqueous solution to be filtered can be appropriately determined in consideration of the composition and temperature of the aqueous solution, the amount of seed crystal added, and the like.

As the fluorometal complex compound to be contained in the aqueous solution containing the fluorometal complex compound, there can be mentioned a compound represented by the following general formula (I). During _{A a M b F c (I} ) formula, A is a hydrogen atom, an alkali metal atom, one or more atoms selected from the group consisting of ammonium group and coordinated water or the like, M is a metal , A, b and c are
This is a number that makes the complex compound electrically neutral. To form this fluorometal complex compound, an acid or salt soluble in water is used. A includes, in addition to a hydrogen atom, an alkali metal atom such as lithium, sodium, potassium, rubidium, and cesium; and an ammonium group and coordinating water. Examples of M (metal) include titanium, silicon, zirconium, niobium, germanium, aluminum, indium, tin, zinc, and copper. However, it is not limited to these metals. When b is 1, c is usually 6, and then a
Is 2 or 3 depending on the valence of. Typically, it can be represented by A ₃ MF ₆ or A ₂ MF ₆ . However, a polynuclear complex compound having a plurality of metal atoms (M) may be used.

The aqueous solution containing the above fluorometal complex compound can be prepared by dissolving the target metal oxide in hydrofluoric acid. Alternatively, the hydroxide or oxyhydroxide of the desired metal is dissolved in an aqueous solution of an alkali metal hydrogen difluoride such as ammonium hydrogen difluoride or sodium hydrogen difluoride, and the corresponding fluorometal complex is dissolved. Compounds can also be synthesized.
The fluorometal complex compound usually has a metal amount of 10 ⁻⁹ to
An aqueous solution having a concentration of 10 mol / L, preferably 10 ^-6 to 10 ^-1 mol / L is used. Here, the aqueous solution may be an aqueous solution containing excess hydrogen fluoride used for synthesizing the metal complex compound.

The fluoride ion scavenger used in the present invention may be any as long as it can trap a fluorine ion from an aqueous solution containing a fluorometal complex compound and deposit a metal oxide thin film. Generally, a fluoride ion scavenger includes a homogeneous system used by being dissolved in a liquid phase and a heterogeneous system which is a solid. Depending on the purpose, either one of these two may be used or both may be used.

The homogeneous fluoride ion scavenger reacts with hydrogen fluoride to form a stable fluoro complex compound and / or fluoride, thereby shifting the equilibrium of fluorine ions so as to deposit a metal oxide thin film. It is to let. Besides boric acid such as orthoboric acid and metaboric acid, examples thereof include aluminum chloride, sodium hydroxide, and aqueous ammonia. Such a capture agent is usually used in the form of an aqueous solution, but may be added in the form of a powder and dissolved in the system. Such addition of the scavenger may be performed once or several times intermittently, or may be performed continuously at a controlled feed rate, for example, at a constant rate.

As the substrate, a wide range of substances for supporting the metal oxide thin film can be used. Examples of such a substrate include glass, metal, ceramics, and organic polymer materials (plastic). further,
SiO ₂ , Al ₂ O ₃ , Z
A substrate on which a thin film of rO ₂ , ITO, CaF ₂ or the like is formed can also be used as a substrate. Furthermore, the shape and form of the base material are arbitrary, and are not limited to plate shapes, and those having complicated shapes can also be used. For example, it can be a bulk, plate, or porous body.

The substrate may be immersed in the aqueous solution of the fluorometal complex compound either before, during or after the addition or insertion of the fluoride scavenger. However, when using a substrate that may be affected by the system, attention must be paid to the composition of the solution, the reaction conditions, and the timing of immersion. Also, while the substrate is immersed in the aqueous solution of the fluorometal complex compound, the substrate is moved by rotating or the like,
Alternatively, the uniform deposition of a thin film can be promoted by stirring the aqueous solution. The reaction temperature can be arbitrarily set within a range in which the system maintains an aqueous solution. Is more preferable.
The reaction time is also arbitrary. For example, when the target precipitate is large, the reaction time can be lengthened accordingly. The temperature difference between the aqueous solution and the base material immediately before immersion is preferably 15 ° C. or less from the viewpoint of producing a uniform thin film.

In this manner, a metal oxide thin film can be formed on the surface of the substrate. The precipitate thus formed is:
In particular, a metal oxide thin film crystallized according to conditions can be obtained as a precipitate without a heating step such as firing. However, a heating step may be provided according to the purpose. Metal oxide thin film obtained by the method of the present invention, depending on the type of fluorometal complex compound used, for example, titanium,
Silicon, zirconium, niobium, germanium,
The thin film contains one or more kinds of oxides of aluminum, indium, tin, zinc, and copper. Further, the metal oxide thin film includes a metal oxide thin film doped with metal ions.

The method for producing a metal oxide thin film of the present invention can be divided into, for example, the following three modes. A first aspect is a method for forming a thin film made of a metal oxide derived from a fluorometal complex compound. When forming a thin film made of a single metal oxide, an aqueous solution containing one type of fluorometal complex compound is used. When a thin film composed of a plurality of metal oxides is to be formed, an aqueous solution containing two or more fluorometal complex compounds is used. In this case, two kinds of metal oxides derived from two or more fluorometal complex compounds are used. It is preferable to carry out the reaction in the presence of the above seed crystal. This is because the use of a seed crystal of a metal oxide to be deposited causes any deposited metal oxide to be a stable phase.

A second aspect of the present invention is a method for producing a metal oxide thin film derived from a fluorometal complex compound doped with metal ions. In this embodiment, the formed thin film is a metal ion-doped metal oxide. As metal ions to be doped into the metal oxide, for example, silver ions, copper ions,
Platinum ion, vanadium ion, chromium ion, manganese ion, iron ion, cobalt ion and the like can be mentioned. However, any metal ion derived from a compound soluble in an aqueous solution containing the fluorometal complex compound can be doped.

Examples of the water-soluble metal compound include Ag
F xH₂O, AgNO₃, Rh (NO₃)₃・ 2H₂
O, Cu (NO₃)₂・ 3H₂O, Cr (NO₃)₃・ X
H₂O, CuF₂・ 2H₂O, CuCl₂・ 2H₂O,
PtCl₄・ 5H₂O, VOSiO₄・ 2H₂O, VO
Cl₃, V₂O₅, Cr₂(SO₄)₃・ 18H
₂O, CrCl₃・ XH₂O, MnCl₂・ 4H₂O,
MnCl₂, Mn (NO₃)₂・ 6H₂O, MnSO₄
・ 6H₂O, MnF₂, MnF₃・ 3H₂O, FeCl
₂・ 4H₂O, FeCl₂, FeCl₃・ 6H₂O, F
eCl₃, Fe (NO₃)₃・ 9H₂O, FeSO₄・
7H₂O, FeSO₄, (NH₄) Fe (SO ₄)₃・
xH₂O, Co (NO₃)₂・ 6H₂O, CoSO₄・
7H₂O, NiCl₂・ 6H₂O, Ni (NO₃)₂・
6H₂O, NiSO₄, Cu (NO₃)₂・ 3H₂O,
CuSO₄・ 5H₂O, CuSO₄, CuCl₂・ 2H
₂O, CuF₂・ 2H₂O, CuCl, Sc (SO₄)
₃・ XH₂O and the like are exemplified.

The concentration of the water-soluble metal compound can be, for example, in the range of 10 ^-4 to 10 mol per liter of the treatment liquid in consideration of the solubility and the doping amount of the thin film. Further, the water-soluble metal compound can be replenished during the reaction.

The third aspect is a method for producing a thin film containing fine particles in a metal oxide derived from a fluorometal complex compound.
This thin film can be formed by adding and dispersing fine particles in an aqueous solution containing a fluorometal complex compound, and depositing the thin film from the aqueous solution. Examples of the fine particles include metal colloid particles, metal oxide colloid particles, and organic particles. Examples of the metal colloid particles include Cu, Ag, and Pt. As metal oxide colloid particles, for example, Fe ₂
O ₃ , Cu ₂ O, CuO and the like can be given. Examples of the organic particles include polystyrene, polyethylene terephthalate, acrylic, and polycarbonate. The particle size of the fine particles and the amount added to the aqueous solution can be appropriately changed depending on the pore size of the filter used and the intended thin film. However, considering the dispersibility of the fine particles in an aqueous solution and the state of existence in a thin film, the particle diameter is
For example, it can be in the range of 10 ^{−3 to 1} μm.
The amount of the fine particles added to the aqueous solution is, for example, 10 to 1 liter of the treatment liquid in consideration of the concentration of the fine particles in the thin film.
It can range from ^-2 to 10 ² g. Fine particles can be added and replenished during the reaction in the same manner as the seed crystal.

It is to be noted that two or more of the above three embodiments can be combined to simultaneously form a thin film containing two or more substances.

[0025]

The present invention will be described in more detail with reference to the following examples.

Example 1 As a fluoro complex metal compound, ammonium hexaflur
Orotitanate (NH ₄)₂TiF₆And this is 2
14 g was dissolved in 1 liter of water and stirred. Then get
TiO₂Preparing anatase microparticles in pure water
The solution obtained by allowing the solution suspended in
0 ml was added, and the mixture was similarly stirred and homogenized. The resulting aqueous solution
Was quickly added and stirred. As above
The aqueous solution for precipitation prepared as described above was placed in the film forming vessel shown in FIG.
It was transferred and immersed in a water tank maintained at 25 ° C. Then the initial
NA35 glass substrate at a temperature of 25 ° C (50 x 70 x 1 mm)
Submerged so that the substrate surface is perpendicular to the surface of the aqueous solution for deposition
did. The aqueous solution for deposition in the film forming vessel is filtered using a pump.
Circulated through filter (pore size: 150 nm). This circulation
Large size TiO with ring₂Aqueous solution with particles removed
The liquid was returned to the film forming container. The circulation amount of the aqueous solution is about 3
It was adjusted to be 0 ml / min. Keep this state
While standing for 10 hours. After the processing time has elapsed,
Remove from aqueous solution for precipitation, wash gently
Dry and TiO₂A substrate on which a thin film was deposited was obtained. Profit
The thin film shows uniform interference reflected light and light scattering.
And the film was highly transparent. For stylus type film thickness measuring instrument
As a result of the measurement, the difference in film thickness was Max 8 nm.
Was.

Comparative Example 1 A substrate on which a TiO ₂ thin film was deposited was obtained in the same manner as in Example 1 except that the aqueous solution for deposition was not circulated by a pump or filtered. The resulting thin film was found to be visually non-uniform, indicating different interference reflected light. As a result of measurement using a stylus-type film thickness measuring device, the difference in film thickness was Max 51.
nm.

Example 2 As a fluoro complex metal compound, ammonium hexaflur
Orotitanate (NH ₄)₂TiF₆And this is 2
14 g was dissolved in 1 liter of water and stirred. Then get
TiO₂Preparing anatase microparticles in pure water
The solution obtained by allowing the solution suspended in
0 ml was added, and the mixture was similarly stirred and homogenized. The resulting aqueous solution
Was quickly added and stirred. As above
The aqueous solution for deposition prepared in
It was transferred and immersed in a water tank maintained at 80 ° C. Then first
Tile substrate (70 × 70 × 1 mm) with initial temperature of 80 ° C
It was immersed so that the surface was horizontal to the liquid surface of the aqueous solution for precipitation.
The aqueous solution for deposition in the film forming vessel is filtered using a pump.
(Pore size: 50 nm). Due to this circulation
Large size TiO₂Form an aqueous solution with particles removed
It was returned to the membrane container. The circulation amount of the aqueous solution is about 130 m
It was adjusted to 1 / min. Do not keep this state
It was left for 2 hours. After processing time, substrate is deposited
Remove from aqueous solution, lightly wash and dry at 70 ° C
TiO₂A substrate on which a thin film was deposited was obtained. Got
The thin film shows uniform interference reflected light and shows light scattering
It was a highly transparent film. Measurement with a stylus-type film thickness measuring instrument
As a result, the difference in the film thickness was Max 15 nm.

Comparative Example 2 A substrate on which a TiO ₂ thin film was deposited was obtained in the same manner as in Example 2 except that the deposition aqueous solution was not circulated by a pump or filtered. The resulting thin film was found to be visually non-uniform, indicating different interference reflected light. As a result of measurement using a stylus-type film thickness measuring device, the difference in film thickness was Max 12
It was 0 nm.

Example 3 As a fluoro complex metal compound, ammonium hexaflur
Orotitanate (NH ₄)₂TiF₆And this is 2
14 g was dissolved in 1 liter of water and stirred. Then get
TiO₂Preparing anatase microparticles in pure water
The solution obtained by allowing the solution suspended in
0 ml was added, and the mixture was similarly stirred and homogenized. The resulting aqueous solution
Was quickly added and stirred. As above
The aqueous solution for precipitation prepared as described above was placed in the film forming vessel shown in FIG.
It was transferred and immersed in a water tank maintained at 50 ° C. Then first
Stainless steel substrate (70 × 50 × 1m)
m) so that the substrate surface is perpendicular to the liquid surface of the aqueous solution for deposition.
Dipped. The aqueous solution for deposition in the film forming vessel is
Circulated through a filter (pore size: 70 nm). this
Large size TiO by circulation₂Water with particles removed
The solution was returned to the film forming container. The circulation amount of the aqueous solution is about
It was adjusted to 80 ml / min. Keep this state
While holding, it was left for 4 hours. After the processing time has elapsed,
Remove from aqueous solution for precipitation, wash gently
Dry and TiO₂A substrate on which a thin film was deposited was obtained. Profit
The thin film shows uniform interference reflected light and light scattering.
And the film was highly transparent. For stylus type film thickness measuring instrument
As a result of the measurement, the difference in film thickness was Max 7 nm.
Was.

Comparative Example 3 A substrate on which a TiO ₂ thin film was deposited in the same manner as in Example 3 except that the deposition aqueous solution was not circulated by a pump or filtered, and the initial temperature of the stainless metal substrate was 25 ° C. I got The resulting thin film was found to be visually non-uniform, indicating different interference reflected light. As a result of measurement using a stylus-type film thickness measuring device, the difference in film thickness was Max 40 nm.

Example 4 As a fluoro complex metal compound, ammonium hexaflur
Orotitanate (NH ₄)₂TiF₆And use this
14 g was dissolved in 1.6 liter of water and stirred. Next
In the aqueous solution obtained in₂Anatase fine particles in advance
Supernatant obtained by leaving the solution suspended in pure water overnight
50 ml of the liquid was added, and the mixture was similarly stirred and homogenized. further,
V₂O₅The supernatant obtained by dissolving the powder in water is about 0.
4 liters were added to the above homogenized aqueous solution. Obtained
50 g of boron oxide was quickly added to the aqueous solution and stirred. Less than
The aqueous solution for precipitation prepared as described above was prepared as shown in FIG.
It was transferred to a membrane container and immersed in a water tank maintained at 40 ° C.
As a film formation substrate, silica (S
iO₂) Coated with an anti-reflective coating
Using plastic substrate (50 × 70 × 5mm)
Was. The substrate surface of the substrate with an initial temperature of 40 ° C.
It was immersed perpendicular to the surface (see FIG. 1). Deposition container
The aqueous solution for precipitation is filtered using a pump (pore size: 1).
00 nm). Due to this circulation, large
Large size TiO₂An aqueous solution from which particles have been removed is placed in a film forming container.
I put it back. The circulation amount of the aqueous solution is about 50 ml / min
It was adjusted to become. 2 o'clock while keeping this state
Left for a while. After the treatment time, the substrate is removed from the aqueous solution for deposition.
Remove, lightly wash, dry at 50 ° C,
Didium ion doped TiO₂Obtain a substrate on which a thin film is deposited
Was. The resulting thin film shows uniform interference reflected light,
The film was highly transparent without light scattering. Stylus type film thickness measurement
As a result of measurement using a constant meter, the difference in film thickness was Max 6 nm.
there were.

Example 5 As a fluoro complex metal compound, ammonium hexaflur
Orotitanate (NH ₄)₂TiF₆And use this
14 g was dissolved in 1.6 liter of water and stirred. Next
In the aqueous solution obtained in₂Anatase fine particles in advance
Supernatant obtained by leaving the solution suspended in pure water overnight
50 ml of the liquid was added, and the mixture was similarly stirred and homogenized. further,
V₂O₅The supernatant obtained by dissolving the powder in water is about 0.
4 liters were added to the above homogenized aqueous solution. Obtained
50 g of boron oxide was quickly added to the aqueous solution and stirred. Less than
The aqueous solution for precipitation prepared as described above was prepared as shown in FIG.
It was transferred to a membrane container and immersed in a water tank maintained at 50 ° C.
A soda lime glass substrate (70 × 50 ×
1 mm). Substrate surface of initial temperature 50 ℃
It was immersed so as to be horizontal to the surface of the aqueous solution (see FIG.
See). The aqueous solution for deposition in the film forming vessel is filtered using a pump.
Circulated through filter (pore size: 70 nm). This circulation
Due to the large size of TiO₂Aqueous solution with particles removed
Was returned to the film forming container. The circulation amount of the aqueous solution is about 80
It was adjusted to be ml / min. Keep this state
For 2 hours. Substrate is deposited after processing time
Remove from aqueous solution, wash lightly, and dry at 70 ° C
After drying, vanadium ion doped TiO₂Deposited thin film
Obtained substrate was obtained. The resulting thin film provides uniform interference reflected light.
This was a transparent film having no light scattering.
As a result of measurement using a stylus-type film thickness measuring instrument, the difference in
x 10 nm.

[0034]

As described above, according to the present invention,
While maintaining the ability to form oxide thin films at room temperature and pressure, which is a feature of the aqueous solution deposition method, it solves the problem of non-uniform thin films, which is a drawback of the method. An object thin film can be obtained. The metal oxide thin film obtained by the manufacturing method of the present invention can be a thin film having a high uniformity and a large thickness as compared with a metal oxide thin film formed by a conventional aqueous solution deposition method. Can be applied.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an apparatus for manufacturing a thin film (when a film forming substrate is arranged perpendicularly to a film forming solution surface).

FIG. 2 is a schematic explanatory view of a thin film manufacturing apparatus (when a film forming substrate is horizontally arranged on a film forming solution surface).

FIG. 3 is a photograph instead of a drawing showing the surface condition of a thin film (a) formed without filtration and a thin film (b) formed by filtration according to the production method of the present invention.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshinobu Miura 2-7-5 Nakaochiai, Shinjuku-ku, Tokyo F-term in Hoya Corporation (reference) 4G042 DA01 DB08 DB11 DD02 DE04 DE14 4G047 CA02 CB05 CC03 CD02 4G059 AA01 AC30 EA01 EA02 EA03 EA04 EA05 EA07 EB05

Claims (6)

[Claims] 1. A method for adding a fluorine scavenger to an aqueous solution containing a fluorometal complex compound to deposit a metal oxide thin film derived from the fluorometal complex compound on a substrate immersed in the aqueous solution. Producing a metal oxide thin film, wherein the deposition of the metal oxide thin film is performed while continuously or intermittently filtering a part of the aqueous solution in the presence of a seed crystal of the metal oxide. Method. 2. An aqueous solution containing a fluorometal complex compound contains a water-soluble metal compound, and deposits a metal oxide thin film derived from a fluorometal complex compound doped with metal ions derived from the water-soluble metal compound. The production method described in 1. 3. The method according to claim 1, wherein the fluorometal complex compound is a fluorotitanium complex compound, and the metal oxide is TiO ₂ . 4. The production method according to claim 1, wherein the filtration of the aqueous solution is performed using a filter having a pore size that allows the seed crystal to pass through and capture particles having a particle size larger than the seed crystal. . 5. The method according to claim 1, wherein the aqueous solution is filtered using a filter having a pore size of 150 nm or less. 6. The production method according to claim 1, wherein the material of the substrate is glass, plastic, metal, ceramics or a composite thereof.